1. Field
Apparatuses consistent with exemplary embodiments relate to fluid machines with variable vanes, and more particularly, to fluid machines that may be conveniently maintained because a driving assembly of the fluid machine may be easily disconnected/connected from/to a case of the fluid machine.
2. Description of the Related Art
In a fluid machine such as a compressor or an expander, a fluid flow control device such as an inlet guide vane (IGV) or a variable geometry diffuser (VGD) is used to control a flow rate to increase efficiency or to control an operation region (i.e., an operation envelop) to implement stability control.
In a device such as an IGV or a VGD, vanes are disposed at a fluid flow passage and rotated to adjust the size of the fluid flow passage. In the related art, in order to rotate the vanes, a motor and an actuator linkage for transmitting the rotation force of the motor are also integrated and assembled in the fluid machine.
U.S. Pat. No. 6,527,508 discloses a technology for rotating vanes by using crank arms in variable geometry turbo-chargers. By this operation mechanism, the vanes may be rotated by a predetermined angle. A motor and an actuator linkage have to be installed in a casing of the fluid machine in order to drive the crank arms. Also, a seal ring has to be disposed between the casing and the actuator linkage in order to prevent the leakage of a fluid from the fluid machine. Thus, in such fluid machine described above, it is difficult to repair the seal ring and the actuator linkage or replace aged components. Because all electric lines and mechanical components such as fluid outlet pipes and fluid inlet pipes connected to the fluid machine have to be first disconnected in order to disconnect the motor and the actuator linkage from the casing of the fluid machine, the maintenance of the fluid machine is difficult, time consuming, and costly.
Similarly, Japanese Patent Laid-Open Publication No. 2001-027124 discloses a fluid machine that rotates a variable nozzle by using an air cylinder. However, in this fluid machine, the air cylinder and a link assembly for transmitting the driving force of the air cylinder to a ring rotating a variable nozzle are connected to a casing of the fluid machine and therefore, the components are very difficult to disconnect. Also, because electric lines and pipes connected to the fluid machine have to be first disconnected in order to perform maintenance on the air cylinder and the link assembly, the maintenance of the fluid machine is also difficult and time consuming.
U.S. Patent Application Publication No. 2012-0121403 discloses a structure in which a rotary actuator is connected to a spacer ring connected to a casing of a compressor and a driving force of the rotary actuator is transmitted to vanes through a driving shaft fixed to a spacer ring thereby driving an IGV of a centrifugal compressor. In this fluid machine, the rotary actuator is fixed to the spacer ring by an attachment bracket and a pneumatic cylinder is disposed outside the driving shaft. Thus, because the electric lines and pipes connected to the fluid machine have to be first disconnected and then the spacer ring, the attachment bracket, the rotary actuator, and the driving shaft have to be disconnected in order to perform maintenance on components such as seal rings and the rotary actuator, the maintenance of the fluid machine is also difficult, time consuming, and costly.
In the fluid machine of U.S. Patent Application Publication No. 2012-0121403, some vanes are directly connected to a driving shaft of a rotary actuator, and other vanes are indirectly driven by a link and a driving shaft rotated by a main crank arm. According to such a structure of the fluid machine, because a high driving force is necessary to drive a driving ring, vanes, and links connected to the respective vanes, the volume of the rotary actuator increases. Also, because the space required for installing the driving ring, the vanes, and the links connected to the respective vanes increases, the size of the fluid machine increases and the structure thereof becomes more complicated.